1. Field of the Invention
The present invention relates to a three-dimensional circuit structure and a manufacturing method thereof. More particularly, the present invention relates to a multilayer three-dimensional circuit structure and a manufacturing method thereof.
2. Description of Related Art
In recent years, with rapid progress of electronic technologies and advancement of high-tech electronic industry, human-oriented electronic products with superior performance have brought forth a new era and have been designed to cater to the trend of being light, thin, short, and small. Generally, according to the pertinent art, a circuit board for hosting and electrically connecting a plurality of electronic devices is disposed in a casing for protecting the circuit board and the electronic devices. Nonetheless, since shapes of the electronic devices are limited to be in conformity with a shape and a dimension of the circuit board, most of the electronic devices are two-dimensional rather than three-dimensional.
In order to directly form signal traces on the circuit board having a three-dimensional structure in replacement of the conventional circuit board, a molded interconnect device (MID) equipped with both electronic and mechanical functions in a three-dimensional structure was proposed, such that printed circuit boards are no longer required to be planar. By conducting the concept of MID, a three-dimensional circuit structure can be formed on a surface of a three-dimensional structure, so as to increase usable space within the casing and miniaturizing the electronic devices to a better degree.
FIG. 1 is a schematic cross-sectional view of a conventional three-dimensional circuit. Referring to FIG. 1, a conventional three-dimensional circuit 100 includes a three-dimensional structure 110 and a three-dimensional circuit structure 120 that is disposed on a surface 112 of the three-dimensional structure 110. However, the conventional three-dimensional circuit 100 merely has a single-layer three-dimensional circuit structure 120. Hence, a surface area of the three-dimensional structure 110 must be sufficient enough to accommodate all of the three-dimensional circuit structures 120. Namely, the three-dimensional structure 110 is unlikely to host all of the three-dimensional circuit structures 120, give that the surface area of the three-dimensional structure 110 is rather small.